Department of Animal Science and Technology, Chung-Ang University, Anseong-si, Gyeonggi-do 17546, Republic of Korea.
Department of Animal Science and Technology, Chung-Ang University, Anseong-si, Gyeonggi-do 17546, Republic of Korea.
Poult Sci. 2023 Jul;102(7):102771. doi: 10.1016/j.psj.2023.102771. Epub 2023 May 2.
The current experiment was conducted to investigate the effect of individual or combination of dietary betaine (Bet) and glycine (Gly) on productive performance, stress response, liver health, and intestinal barrier function in broiler chickens raised under heat stress (HS) conditions. A total of four hundred twenty 21-d-old Ross 308 broiler chickens were randomly allotted to 1 of 5 dietary treatments with 7 replicates. Birds in treatment 1 were raised under the thermoneutral condition (TN; 23 ± 0.6°C). Birds in other 4 treatment groups were subjected to a cyclic HS by exposing them to 32 ± 0.9°C for 8 h/d (from 09:00 to 17:00 h) and 28 ± 1.2°C for the remaining time for 14 d. Birds were fed a basal diet in TN condition (TN-C) and one group in HS conditions (HS-C), whereas other birds raised under HS conditions were fed the basal diet supplemented with 0.20% Bet (HS-Bet), 0.79% Gly (HS-Gly), or their combination (0.20% Bet + 0.79% Gly; HS-Bet+Gly). Results indicated that birds in HS-Bet, HS-Gly, or HS-Bet+Gly treatment had higher (P < 0.05) final BW and BW gain, but lower (P < 0.05) feed conversion ratio (FCR) than those in HS-C treatment. However, values for improved final BW, BW gain, and FCR by dietary treatments were lower (P < 0.05) than those measured in TN-C treatment. Under HS conditions, birds in HS-Bet, HS-Gly, or HS-Bet+Gly treatment had lower (P < 0.05) heterophil to lymphocyte ratio than those in HS-C treatment. Birds in HS-Gly or HS-Bet+Gly treatment had higher (P < 0.05) villus height and goblet cell number than birds in HS-C treatment. Intestinal permeability was higher (P < 0.05) in all HS-treatment groups than in TN-C treatment, but it was not affected by dietary treatment. In conclusion, individual supplementation of 0.20% Bet or 0.79% Gly in diets alleviates the negative effect of HS in broiler chickens. However, the synergistic effect of the combination of 0.20% Bet and 0.79% Gly in broiler diets seems lower than expected.
本实验旨在研究饲粮中单添加甜菜碱（Bet）或甘氨酸（Gly）或两者组合对热应激条件下肉鸡生产性能、应激反应、肝脏健康和肠道屏障功能的影响。将 420 只 21 日龄 Ross 308 肉鸡随机分为 5 种饲粮处理，每个处理 7 个重复。处理 1 的肉鸡饲养在常温（TN；23±0.6°C）条件下。其他 4 个处理组的肉鸡通过在 32±0.9°C 下暴露 8 小时/天（从 09:00 到 17:00）和在 28±1.2°C 下暴露 16 小时来进行周期性 HS，持续 14 天。TN 条件下的肉鸡饲喂基础饲粮（TN-C），HS 条件下的一组肉鸡饲喂基础饲粮（HS-C），而 HS 条件下的其他肉鸡饲喂基础饲粮，添加 0.20%甜菜碱（HS-Bet）、0.79%甘氨酸（HS-Gly）或两者的组合（0.20%甜菜碱+0.79%甘氨酸；HS-Bet+Gly）。结果表明，与 HS-C 处理相比，HS-Bet、HS-Gly 或 HS-Bet+Gly 处理的肉鸡终重和增重更高（P＜0.05），但饲料转化率（FCR）更低（P＜0.05）。然而，饲粮处理对终重、增重和 FCR 的改善效果低于 TN-C 处理（P＜0.05）。在 HS 条件下，与 HS-C 处理相比，HS-Bet、HS-Gly 或 HS-Bet+Gly 处理的肉鸡异嗜性白细胞与淋巴细胞比率更低（P＜0.05）。HS-Gly 或 HS-Bet+Gly 处理的肉鸡的绒毛高度和杯状细胞数量高于 HS-C 处理（P＜0.05）。与 TN-C 处理相比，所有 HS 处理组的肠道通透性均更高（P＜0.05），但不受饲粮处理的影响。综上所述，饲粮中单添加 0.20%甜菜碱或 0.79%甘氨酸可缓解 HS 对肉鸡的负面影响。然而，0.20%甜菜碱和 0.79%甘氨酸在肉鸡饲粮中的组合协同作用似乎低于预期。
